Field of the Invention
The invention relates to an optical lens and an electronic device, and particularly relates to an optical imaging lens and a mobile device.
Description of Related Art
In recent years, along with wide use of mobile electronic products such as mobile phones, digital cameras, etc., techniques related to image module are quickly developed, and the image module mainly includes components such as an optical imaging lens, a module holder unit, a sensor, etc., and a thinning and lightweight trend of the mobile phones and the digital cameras increases a miniaturization demand of the image module. Along with technology improvement and size reduction of charge coupled devices (CCD) and complementary metal oxide semiconductors (CMOS), a length of the optical imaging lens installed in the image module is also required to be correspondingly shortened. However, in order to avoid decline of image capturing effect and image capturing quality, when the length of the optical imaging lens is shortened, the good optical performance has to be taken into consideration. The most important characteristics of the optical imaging lens are imaging quality and a volume thereof.
Specifications of the mobile electronic products (for example, mobile phones, cameras, tablet personal computers, personal digital assistants, vehicle camera device, etc.) change rapidly, and optical lens sets serving as key components thereof are also developed in diversified ways. Applications of the optical lens sets not only include image capturing and video recording, but also include environment monitoring, driving data recording, etc., and along with progress of image sensing technology, consumers have higher demand on imaging quality. Therefore, the design of the optical lens group not only requires to achieve good imaging quality and a smaller lens space, but also has to consider improvement of field of view and the size of an aperture due to a dynamic and light inadequate environment.
However, regarding the design of the optical imaging lens, in order to fabricate the optical imaging lens with both characteristics of good imaging quality and miniaturization, it is not enough to purely scale down the lenses with good imaging quality, and a material property is also involved, and practical problems in production such as an assembling yield, etc., are also considered.
A technical difficulty for fabricating the miniaturized lens is obviously higher than that of the conventional lens, so that it is still a target of the industry, government and academia to produce the optical imaging lens complied with demands of consumer electronics, and keep improving the imaging quality thereof.
Moreover, regarding a three-piece lens structure, in the conventional optical imaging lens, a distance between an object-side surface of a first lens element and an image plane on an optical axis is too large, which is of no avail for thinning the mobile phones and digital cameras.